Spin relaxometry based molecular sequencing

ABSTRACT

A method and system for detecting a target molecule. The method includes allowing a fluid containing the target molecule to pass by a complementary moiety attached to a paramagnetic ion so as to cause the complementary moiety and the paramagnetic ion to change a position. A magnetic effect change caused by the change in position of the paramagnetic ion is detected. The target molecule is identified based on the identity of the complementary moiety and the detected magnetic effect change.

FIELD

The present disclosure generally relates to a system and a method for detecting target molecules based on detection of a magnetic effect change, which may be based on a position change of a paramagnetic ion.

BACKGROUND

There has been significant scientific effort directed towards sequencing of DNA, proteins, and other target molecules. Such sequencing techniques often include amplification, where the target molecules must be processed so as to be concentrated, and further may include labeling of molecules as indicators.

Ionic current sensing schemes have been proposed and developed for amplification-free, label-free sequencing of DNA, proteins, and other target molecules. In one scheme, a single strand DNA with components arranged serially along the strand is passed through a nano-pore of a substrate. The ionic current is measured from one side of the substrate to the other side. When a particular component of the strand is in the nano-pore, the ionic current is reduced due to the presence of the component in the nano-pore. The amount of ionic current measured is based on the particular component present in the nano-pore. Thus, the target components of a DNA sequence may be identified to some extent based on measuring the ionic current.

This method of measuring the ionic current, however, lacks good specificity to the particular molecular component identified, and calibration is required for each nanopore. Further this method is interpretation error prone, and may have error rates of 15% or more.

SUMMARY

According to some embodiments, a method for detecting a target molecule may comprise: allowing a fluid containing the target molecule to pass by a complementary moiety attached to a paramagnetic ion so as to cause the complementary moiety and the paramagnetic ion to change a position; detecting a magnetic effect change caused by the change in position of the paramagnetic ion; and identifying the target molecule based on the identity of the complementary moiety and the detected magnetic effect change.

According to some embodiments, the detecting a magnetic effect change comprises detecting a change in spin relaxation of an electron spin center.

According to some embodiments, the electron spin center comprises one or more of diamond nitrogen vacancy (DNV) centers, defect centers in silicon carbide, or defect centers in silicon.

According to some embodiments, the detecting a magnetic effect change comprises detecting a change in the spin relaxation time of the electron spin center.

According to some embodiments, the detecting a magnetic effect change comprises detecting a change in photoluminescence from the electron spin center.

According to some embodiments, the detecting a magnetic effect change is performed by detecting a change in an electrical read out.

According to some embodiments, the magnetic effect change is detected based on the fluid containing the target molecule passing through a pore of a substrate.

According to some embodiments, the method further comprises detecting a change in ionic current as the target molecule is in the pore, wherein the identifying the target molecule is further based on the detected change in the ionic current.

According to some embodiments, the substrate comprises an electron spin center, and the detecting a magnetic effect change comprises detecting a change in spin relaxation of the electron spin center.

According to some embodiments, the substrate comprises diamond, and the electron spin center comprises one or more diamond nitrogen vacancy (DNV) centers.

According to some embodiments, the substrate comprises DNV centers arranged in a band surrounding the pore.

According to some embodiments, the paramagnetic ion is attached to an inner surface of the pore via a ligand attachment of the paramagnetic ion.

According to some embodiments, the paramagnetic ion is attached to the complementary molecule. According to some embodiments, the paramagnetic ion is one of Gd³⁺, another Lathanide series ion, or Manganese.

According to some embodiments, the target molecule is part of a DNA molecule.

According to some embodiments, the identifying the target molecule is further based on a second effect detecting technique other than the magnetic effect change.

According to some embodiments, a method for detecting target moieties of a target molecule may comprise: allowing a fluid containing the target molecule to pass by a plurality of complementary moieties, each of the plurality of complementary moieties attached to a different respective paramagnetic ion and specific to a respective of the target moieties, so as to cause a respective complementary moiety and paramagnetic ion to change a position; detecting a magnetic effect change caused by the change in position of a respective of the paramagnetic ions for each of the plurality of target moieties; and identifying the target moieties based on the identities of the complementary moieties and the detected magnetic effect changes.

According to some embodiments, the detecting a magnetic effect change for each of the plurality of target moieties comprises detecting a change in spin relaxation of an electron spin center.

According to some embodiments, a system for detecting a target molecule comprises: a substrate comprising an electron spin center; a complementary moiety attached to a paramagnetic ion, which is attached to the substrate; a magnetic effect detector arranged to detect a magnetic effect change of the electron spin center caused by a change in position of the paramagnetic ion due to the target molecule passing by the complementary moiety; and a processor configured to identify the target molecule based on the identity of the complementary moiety and the detected magnetic effect change.

According to some embodiments, the magnetic effect detector may comprise a light source arranged to direct excitation light onto the electron spin center; and a light detector arranged to receive photoluminescence light from the electron spin center based on the excitation light.

According to some embodiments, the system for detecting target moieties of a target molecule comprises: a substrate comprising a plurality of electron spin centers; a plurality of complementary moieties attached to respective of a plurality of paramagnetic ions, which are attached to the substrate, each of the plurality of complementary moieties attached to a different respective paramagnetic ion and specific to a respective of the target moieties; a magnetic effect detector arranged to detect, for each of the target moieties, a magnetic effect change of a respective electron spin center caused by a change in position of a respective of the paramagnetic ions due to the target moieties passing by a respective of the complementary moieties; and a processor configured to identify the target moieties based on the identities of the complementary moieties and detected magnetic effect changes.

According to some embodiments, a method for detecting target moieties of a target molecule may comprise: allowing a fluid containing the target molecule to pass by a plurality of complementary moieties, each of the plurality of target moieties attached to a different respective paramagnetic ion and specific to a respective of the complementary moieties, so as to cause a respective target moiety and paramagnetic ion to change a position; detecting a magnetic effect change caused by the change in position of a respective of the paramagnetic ions for each of the plurality of target moieties; and identifying the target moieties based on the identities of the complementary moieties and the detected magnetic effect changes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a system for detecting a target molecule according to embodiments.

FIG. 2 is a top view of a pore of the substrate shown in FIG. 1.

FIG. 3 is a magnified cross-sectional view of a portion of the side wall of a pore of the substrate shown in FIG. 1.

FIG. 4A is a graph illustrating the photoluminescence of a spin center as a function of time in the case where the paramagnetic ion is relatively far from the spin center.

FIG. 4B is a graph illustrating the photoluminescence of a spin center as a function of time in the case where the paramagnetic ion is relatively close to the spin center.

FIG. 5 illustrates a target molecule with individual target moities passing through a pore of the substrate.

FIG. 6 is a graph illustrating the magnetic effect signal as a function of time for four different spin centers.

FIG. 7 is a schematic diagram illustrating a system for detecting a target molecule according to embodiments using both a magnetic effect detector and a second effect detector.

FIG. 8 illustrates embodiments of the substrate of the system which includes electronic read out of the magnetic spin change.

DETAILED DESCRIPTION

According to some embodiments, a system and method for identifying target moieties is provided based on complementary moieties specific to the target moieties, and is further based on using detection of a magnetic effect change caused by an associated paramagnetic ion. Because the technique can be specific, it is less error prone. The system of some embodiments allows for identifying components of DNA, for example, and thus sequencing of DNA, without requiring DNA amplification chemistry, is possible. According to some embodiments, the system and method can thus avoid the complexity and cost of amplification chemistries. Sensing of extremely small quantities of analyte are possible, and sequencing speed may be improved. The system and method are applicable to a number of different applications such as forensics, diagnosis, therapeutics, predictive medicine, and synthetic biology.

Further the system and method according to embodiments allows for further advantages. A highly sensitive optical readout is possible. The system can be configured for ultra-fast readout, such as by using an electronic readout. The system can be combined with other detection schemes such as an ion-current detection method. In some embodiments, a carbon chain with high molecular weight is connected to the sensing material such as an magneto-optical defect center material. The connection may be covalent, ionic, or any other type of bond. The carbon chain includes a moiety with an ionic charge that is complementary to the charge on a potentially sensed material. The sensor chain with the moiety is placed near a fluid stream that may contain unknown molecules to be sensed and identified. Before any substance is present to be sensed, the chain with the moiety is permitted to be present in the stream where its location and magnetic field may be sensed. As a unknown molecule passes by the chain with the moiety the unknown molecule may temporarily bind with moiety causing the moiety to move.

FIGS. 1-3 illustrate a system 100 for detecting a target molecule 190 according to some embodiments. FIG. 1 is a schematic diagram illustrating the system 100. FIG. 1 illustrates a substrate 110 of the system shown in side cross-sectional view. FIG. 2 illustrates the substrate 110 shown in top view. FIG. 3 is a magnified cross-sectional view of a portion of an inner side wall 122 region of a pore 120 in the substrate 110. The system 100 further includes a magnetic effect detector 140 and a processor 146.

The substrate 110 may have one or more electron spin centers 132. The electron spin centers 132 may be diamond nitrogen vacancies (DNV), for example. In this case, the substrate 110 may be formed of diamond material. Alternatively, the electron spin centers 132 may be defect centers in silicon carbide, for example, where the substrate 110 may be formed of silicon carbide, or the electron spin centers 132 may be atomic substitutions in silicon, such as phosphorous in silicon, for example. In general, the electron spin centers 132 may be in magneto-optical defect center material.

The electron spin centers 132 may be arranged in a band 130 about the pore 120. The band 130 of electron spin centers 132 may be disposed at a short distance from the inner wall 122 of the pore 120. For example, the electron spin centers 132 may be disposed at a distance of 1 to 20 nm from the inner wall 122. The distance from the band 130 to the inner wall 122 should be short enough such that an electron spin center 132 may react to the magnetic field due to one of the paramagnetic ions 182. While FIG. 2 illustrates the band to be circular in shape, other shapes such as square are possible, and may depend on the shape of the pore 120. The band 130, may be formed by ion implantation, for example.

The size of the pore 120 will depend upon the particular application and target molecule or moiety. The pore 120 size may be in a range of 1 to 10 nm, for example.

The system 100 further may include one or more complementary moieties 186, each attached to a respective paramagnetic ion 182. The paramagnetic ion 182 in turn may be attached to the inner wall 112 of the pore 120 via a ligand attachment 180 of the paramagnetic ion 182. The ligand attachment is preferably flexible so as to allow the paramagnetic ion 182 to move closer and further from the band 130 of electron spin centers 132 due to the movement of the complementary moiety 186 attached to the paramagnetic ion 182. As one example of attaching the paramagnetic ion 182 of Gd³⁺ to a diamond substrate via the ligand attachment 180, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysulfosuccinimide (NHS) may be used to activate carboxyl groups on the diamond surface so that they react with Gd³⁺ molecules functionalized with amine groups. Complementary molecules, or moieties, could be attached by a number of different chemical linkages. For example, for DNA complementary bases, each base (e.g. adenine, thymine, guanine, or cytosine) could be attached via structures similar to the phosphate-deoxyribose structures that make up the backbone of DNA strands.

Referring to FIG. 3, a target molecule 190 in a fluid 170 is allowed to pass by one of the complementary moieties 182. The complementary moiety 186 is such that it interacts with the target molecule 190, so that complementary moiety 186 changes its position and is drawn closer to the transiting target molecule 190 by interaction forces. For example, the complementary moiety 186 may temporarily bind to a portion of the target molecule 190 thereby causing the complementary moiety 186 to move as the target molecule 190 passes through the pore 120. When the complementary moiety 186 moves, the paramagnetic ion 182 in turn moves because the complementary moiety 186 is attached to the paramagnetic ion 182.

The paramagnetic ion 182 provides a magnetic field which interacts with a spin center 132, and has an effect on the electron spin center 132. The magnetic effect of the spin center 132 changes with the distance from the electron spin center 132 to the paramagnetic ion 182, and is detected by the magnetic effect detector 140. For each paramagnetic ion 182, there should correspond at least one electron spin center 132, which is relatively close to the paramagnetic ion 182 so as to allow for interaction between the paramagnetic ion 182 and the electron spin center 132.

In one embodiment, the magnetic effect is the relaxation time T₁ of the electron spin center 132. For example, the electron spin center 132 may comprise DNV centers, and the paramagnetic ion 182 may be a Gd³⁺ ion. Alternatively, the paramagnetic ion 182 may be another strongly paramagnetic ion such as another Lanthanide series ion, or Manganese. In the case of a Gd³⁺ ion, the magnetic noise from the Gd³⁺ ion spins (S=7/2) induces enhanced relaxation of the NV spins reducing the relaxation time T₁. This magnetic effect of the spin center relaxation time changes with the distance of the Gd³⁺ ion to the electron spin center 132. In particular the spin center relaxation time T₁ decreases as the distance of the Gd³⁺ ion to the electron spin center 132 decreases.

The magnetic effect detector 140 is arranged to detect the magnetic effect change of one of the electron spin centers 132. For example, the magnetic effect detector 140 may detect a change in the relaxation time T₁ of an electron spin center 132 by measuring the photoluminescence emitted by the electron spin center 132 as a function of time, and determining the relaxation time T₁ based on the photoluminescence decay with time.

In the case that the magnetic effect detector 140 detects the photoluminescence of an electron spin center 132 as a function of time, the magnetic effect detector 140 may include a light source 142 arranged to direct excitation light onto the electron spin center 132, and a light detector 144 arranged to receive photoluminescence light from the electron spin center 132 based on the excitation light. The light source 142 will direct excitation light onto a desired electron spin center 132 to measure the photoluminescence from the desired electron spin center 132. In the case the electron spin center 132 is a DNV center, for example, the light source 142 may be a laser or a LED, for example, providing light in the green.

In operation, the distances between spin centers 132 with nearby attached complementary molecules or moieties need not match distances between complementary target molecules or moieties. The spin centers 132 can be spaced to enable convenient individual addressing with laser light through, for example, a confocal microscopy arrangement. Timing of signal readouts will be dictated by time it takes different target molecules or moieties to move past respective complementary molecules or moieties.

FIGS. 4A and 4B illustrate the photoluminescence (PL) of a spin center as a function of time. FIG. 4A illustrates the case where the paramagnetic ion 182 is relatively far from the electron spin center 132, while FIG. 4B illustrates the case where the paramagnetic ion 182 is relatively close to the electron spin center 132. As can be seen from FIGS. 4A and 4B, the relaxation time is larger in the case that the paramagnetic ion 182 is relatively far from the electron spin center 132.

Referring to FIG. 3, the target molecule 190 may comprise a number of individual target moieties 192 and the one or more complementary moieties 186 may comprise a number of different complementary moieties 186 a, 186 b, etc. Each of the complementary moieties 186 a, 186 b is specific to a different individual target moiety 192 a, 192 b. That is, the complementary moiety 186 a interacts most strongly with the individual target moiety 192 a, while the complementary moiety 186 b interacts most strongly with the individual target moiety 192 b. While FIG. 3 only illustrates two individual target moieties 192 a, 192 b and two complementary moieties 186 a, 186 b, in general the number of individual moieties and complementary moieties may be more than two. Further, while FIGS. 1-3 illustrate a single pore 120, the system may include multiple pores, where different target moieties pass through different pores, and where the different target moieties are detected in the different pores by switching interrogation between the pores.

The individual moieties 192 may be attached to a single strand 194 of the target molecule 190. The target molecule in this case may be DNA, and the complementary moieties 186 may be complementary nucleic acid bases.

FIG. 5 illustrates an example of a target molecule 190 with individual target moieties 192 a, 192 b, 192 c, and 192 d passing through a pore 120 of a substrate 110. The pore 120 has complementary moieties 186 a, 186 b, 186 c and 186 d attached to an inner wall 122 of the pore 120. Each of the complementary moieties 186 a, 186 b, 186 c and 186 d is specific to a respective different individual target moiety 192 a, 192 b, 192 c, and 192 d. Further, each of the complementary moieties 186 a, 186 b, 186 c and 186 d corresponds to a different of the electron spin centers 132 a, 132 b, 132 c and 132 d, where the corresponding paramagnetic ion 182 is attached to a portion of the inner wall 122 of the pore 120 so that the paramagnetic ion 182 is relatively close to the electron spin center 132.

As the molecule 190 passes through the pore 120, the first the complementary moiety 186 a will interact with the individual target moiety 192 a and the magnetic effect detector 140 will detect a magnetic effect change of the corresponding electron spin center 132 a. Then, the magnetic effect detector 140 will detect a magnetic effect change of the corresponding electron spin center 132 b for the interaction between the complementary moiety 186 b and the individual target moiety 192 b. In turn, the magnetic effect detector 140 will detect a magnetic effect change of the corresponding electron spin center 132 c for the interaction between the complementary moiety 186 c and the individual target moiety 192 c. Finally, the magnetic effect detector 140 will detect a magnetic effect change of the corresponding electron spin center 132 d for the interaction between the complementary moiety 186 d and the individual target moiety 192 d.

While FIG. 5 illustrates the complementary moieties 186 a-186 d to be arranged in the same order as the respective individual target moieties 192 a-192 d, the ordering may be different. The different electron spin centers 132 allow for different channels of detection of the magnetic effect change, one for each electron spin center 132. Each electron spin center 132 and its associated paramagnetic ion 182 correspond to a different channel, and each channel corresponds to a different target moiety. Thus, the different channels may be interrogated for their respective magnetic effects allowing for specificity of each channel to a respective particular target moiety.

While FIGS. 3 and 5 illustrate the complementary moieties attached to a pore surface via a paramagnetic ion and a ligand attachment, alternatively the paramagnetic ion may be attached to the target molecule or target moiety. The complementary moiety is such that it interacts with the target molecule or target moiety, so that target molecule or target moiety changes its position and is drawn closer to the complementary moiety by interaction forces. When the target molecule or target moiety moves, the paramagnetic ion in turn moves because the target molecule or target moiety is attached to the paramagnetic ion. Thus, it is possible to label either the target molecule or target moiety with the paramagnetic ion, or to label the complementary moiety with the paramagnetic ion as described in earlier embodiments.

FIG. 6 illustrates the magnetic effect signal as a function of time for each of the electron spin centers 132 a-132 d for the arrangement shown in FIG. 5. The magnetic effect signal will change in time order of the order of the electron spin centers 132 a-132 d for the FIG. 5 arrangement. Of course, the magnetic effect signal will be different in time for a different arrangement of the electron spin centers 132 and their corresponding complementary moieties.

Referring back to FIG. 1, the system 100 may include a processor 146. The processor 146 controls the magnetic effect detector 140 to detect the magnetic effect of individual of the electron spin centers 132, and receives the results of magnetic effects from the magnetic effect detector 140.

The processor 140 further may include information regarding the identity of the complementary moieties, and of a target molecule, including target moieties, if any, which will interact with the complementary moieties. The processor 140 further may include information on the correspondence between the complementary moieties and their respective associated spin centers and the arrangement of complementary moieties and their respective associated spin centers. Based on the results of the magnetic effects, and the information regarding the identity of the complementary moieties, or complementary moieties, and possible target molecules or target moieties, the processor may identify the target molecules or target moieties.

In this way, the system 100 allows for the complementary moieties to be labeled because they are specific to particular target molecules or moieties. The labeling provides improved identification of the target molecules or moieties.

The system and method described above using paramagnetic ions for identifying target molecules or moieties, may be combined with other identification techniques to enhance detection. For example, FIG. 7 illustrates a system 200 with the magnetic effect detector 140 as shown in FIG. 1, but additionally including a second effect detector 150 to monitor a second effect which changes upon a target moiety being in the pore 120.

For example, the second effect detector 150 may be an ion current detector, as shown in FIG. 7, with a voltage source 154, ammeter 152 and electrodes 156. The ion current detector detects the ion current in the fluid 170 from one side of the substrate 110 with the pore 120, to the other side of the substrate 110. When a target molecule is in the pore 120, the ionic current is reduced.

The processor 146 controls and receives the ionic current results from the second effect detector 150, and further controls and receives the magnetic effects results from the magnetic effect detector 140. As discussed above with respect to FIG. 1, the processor 146 may identify target molecules or moieties based on the magnetic effect results.

The processor 146 may enhance the identification of target molecules or moieties further using the ionic current results. In this regard, the processor 146 may include information relating the ionic current strength corresponding to the applicable target molecules or target moieties. The processor may identify the target molecule based both on the magnetic effect results, and the second effect results, as well as the information regarding the applicable target molecules or moieties.

FIG. 8 illustrates an embodiment of the substrate 110, where the substrate 110 includes a graphene layer 810 with a pore 120 within the graphene layer 810. This embodiment allows for fast readout of the magnetic spin change of the spin center. The substrate 110 may include a support structure 840, upon which the graphene layer 810 is supported. The graphene layer 810 may include a number of sublayers. The support structure 840 may be formed of silicon nitride, for example.

In FIG. 8, the electron spin centers 132 may formed in separate nano-structures 820. The nano-structures 820 may be about 5 to 100 nm in size. For example, if the electron spin centers 132 are DNV centers, the nano-structures 820 may be formed of diamond. Each nano-structure 820 has an associated paramagnetic molecule 182, which is attached to the nano-structure 820 via a ligand 180, and a complementary moiety 186 attached to the paramagnetic ion 182.

The substrate 110 further includes a source electrode 830 and a drain electrode 832 formed thereon which allow for electronic readout of the optical excitation of the electron spin centers 132, in contrast to the optical readout provided by the light detector 144 of FIG. 1. The electronic readout may be based on, for example, non-radiative energy transfer (NRET) of the electron spin center 132, which generates an electron-hole pair. Electrical signals due to the NRET of the electron spin centers 132 may be detected using a source electrode 830 and a drain electrode 832, for example.

As described above, according to embodiments, a system and method for identifying target moieties is provided based on complementary moieties specific to the target moieties, and is further based on using detection of a magnetic effect change caused by an associated paramagnetic ion. Because the technique can be specific, it is less error prone. The system allows for identifying components of DNA, for example, and thus sequencing of DNA, without requiring DNA amplification chemistry, is possible. According to embodiments, the system and method can thus avoid the complexity and cost of amplification chemistries. Sensing of extremely small quantities of analyte are possible, and sequencing speed may be improved. The system and method are applicable to a number of different applications such as forensics, diagnosis, therapeutics, predictive medicine, and synthetic biology.

Further, as described above, the system and method according to embodiments allows for further advantages. A highly sensitive optical readout is possible. The system can be configured for ultra-fast readout, such as by using an electronic readout. The system can be combined with other detection schemes such as an ion-current detection method.

The embodiments of the inventive concepts disclosed herein have been described in detail with particular reference to preferred embodiments thereof, but it will be understood by those skilled in the art that variations and modifications can be effected within the spirit and scope of the inventive concepts. 

What is claimed is:
 1. A method for detecting a target molecule comprising: allowing a fluid containing the target molecule to pass by a complementary moiety attached to a paramagnetic ion so as to cause the complementary moiety and the paramagnetic ion to change a position; detecting a magnetic effect change caused by the change in position of the paramagnetic ion comprising detecting a change in spin relaxation of an electron spin center; and identifying the target molecule based on the identity of the complementary moiety and the detected magnetic effect change.
 2. The method of claim 1, wherein the electron spin center comprises one or more of diamond nitrogen vacancy (DNV) centers, defect centers in silicon carbide, or defect centers in silicon.
 3. The method of claim 1, wherein the detecting a magnetic effect change comprises detecting a change in photoluminescence from the electron spin center.
 4. The method of claim 1, wherein the detecting a magnetic effect change is performed by detecting a change in an electrical read out.
 5. The method of claim 1, wherein the magnetic effect change is detected based on the fluid containing the target molecule passing through a pore of a substrate.
 6. The method of claim 5, further comprising: detecting a change in ionic current as the target molecule is in the pore, wherein the identifying the target molecule is further based on the detected change in the ionic current.
 7. The method of claim 5, wherein substrate comprises diamond, and the electron spin center comprises one or more diamond nitrogen vacancy (DNV) centers.
 8. The method of claim 7, wherein substrate comprises DNV centers arranged in a band surrounding the pore.
 9. The method of claim 5, wherein paramagnetic ion is attached to an inner surface of the pore via a ligand attachment of the paramagnetic ion.
 10. The method of claim 1, wherein the paramagnetic ion is attached to the complementary molecule.
 11. The method of claim 1, wherein the paramagnetic ion is one of Gd3+, another Lathanide series ion, or Manganese.
 12. The method of claim 1, wherein the target molecule is part of a DNA molecule.
 13. The method of claim 1, wherein the identifying the target molecule is further based on a second effect detecting technique other than the magnetic effect change.
 14. A method for detecting target moieties of a target molecule comprising: allowing a fluid containing the target molecule to pass by a plurality of complementary moieties, each of the plurality of complementary moieties attached to a different respective paramagnetic ion and specific to a respective of the target moieties, so as to cause a respective complementary moiety and paramagnetic ion to change a position; detecting a magnetic effect change caused by the change in position of a respective of the paramagnetic ions for each of the plurality of target moieties comprising detecting a change in spin relaxation of an electron spin center; and identifying the target moieties based on the identities of the complementary moieties and the detected magnetic effect changes.
 15. The method of claim 14, wherein the electron spin center comprises one or more diamond nitrogen vacancy (DNV) centers, defect centers in silicon carbide, or defect centers in silicon.
 16. The method of claim 14, wherein the detecting a magnetic effect change is performed by detecting a change in an electrical read out.
 17. The method of claim 14, wherein for each of the plurality of target moieties, the magnetic effect change is detected based on the fluid containing the target molecule passing through a pore of a substrate.
 18. The method of claim 17, further comprising: detecting a change in ionic current as the target molecule is in the pore, wherein the identifying the target moieties is further based on the detected change in the ionic current.
 19. The method of claim 17, wherein substrate comprises diamond, and the electron spin centers each comprises one or more diamond nitrogen vacancy (DNV) centers.
 20. The method of claim 14, wherein the target molecule is a DNA molecule and the target moieties are part of the DNA molecule.
 21. The method of claim 14, wherein the identifying the target moieties are further based on a second effect detecting technique other than the magnetic effect change.
 22. A system for detecting a target molecule comprising: a substrate comprising an electron spin center; a complementary moiety attached to a paramagnetic ion, which is attached to the substrate; a magnetic effect detector arranged to detect a magnetic effect change of the electron spin center caused by a change in position of the paramagnetic ion due to the target molecule passing by the complementary moiety; and a processor configured to identify the target molecule based on the identity of the complementary moiety and the detected magnetic effect change.
 23. The system of claim 22, wherein the magnetic effect detector comprises: a light source arranged to direct excitation light onto the electron spin center; and a light detector arranged to receive photoluminescence light from the electron spin center based on the excitation light.
 24. The system of claim 22, wherein the electron spin center comprises one or more diamond nitrogen vacancy (DNV) centers.
 25. The system of claim 22, wherein the substrate comprises a pore, the complementary moiety attached to an inner surface of the pore.
 26. The system of claim 22, wherein the substrate comprises diamond, and the electron spin center comprises one or more diamond nitrogen vacancy (DNV) centers.
 27. The system of claim 25, wherein the substrate comprises diamond nitrogen vacancy (DNV) centers arranged in a band surrounding the pore.
 28. The system of claim 25, wherein paramagnetic ion is attached to an inner surface of the pore via a ligand attachment of the paramagnetic ion.
 29. A system for detecting target moieties of a target molecule comprising: a substrate comprising a plurality of electron spin centers; a plurality of complementary moieties attached to respective of a plurality of paramagnetic ions, which are attached to the substrate, each of the plurality of complementary moieties attached to a different respective paramagnetic ion and specific to a respective of the target moieties; a magnetic effect detector arranged to detect, for each of the target moieties, a magnetic effect change of a respective electron spin center caused by a change in position of a respective of the paramagnetic ions due to the target moieties passing by a respective of the complementary moieties; and a processor configured to identify the target moieties based on the identities of the complementary moieties and detected magnetic effect changes.
 30. The system of claim 29, wherein the magnetic effect detector comprises: a light source arranged to direct excitation light onto one of the electron spin centers; and a light detector arranged to receive photoluminescence light from the one of the electron spin centers based on the excitation light.
 31. The system of claim 29, wherein the electron spin centers each comprise one or more diamond nitrogen vacancy (DNV) centers, defect centers in silicon carbide, or defect centers in silicon.
 32. The system of claim 29, wherein the substrate comprises a pore, the complementary moieties attached to an inner surface of the pore.
 33. The system of claim 29, wherein the substrate comprises diamond, and the electron spin centers comprises diamond nitrogen vacancy (DNV) centers.
 34. The system of claim 33, wherein the substrate comprises diamond nitrogen vacancy (DNV) centers arranged in a band surrounding the pore.
 35. The system of claim 32, wherein paramagnetic ions are attached to an inner surface of the pore via ligand attachments of the paramagnetic ions.
 36. A method for detecting target moieties of a target molecule comprising: allowing a fluid containing the target molecule to pass by a plurality of complementary moieties, each of the plurality of target moieties attached to a different respective paramagnetic ion and specific to a respective of the complementary moieties, so as to cause a respective target moiety and paramagnetic ion to change a position; detecting a magnetic effect change caused by the change in position of a respective of the paramagnetic ions for each of the plurality of target moieties comprising detecting a change in spin relaxation of an electron spin center; and identifying the target moieties based on the identities of the complementary moieties and the detected magnetic effect changes. 